IL203 Optoisolator Transistor with Base - Equivalent & Substitute Parts

Part Overview

The IL203 is a 6-DIP optoisolator with transistor output and base connection, rated for 5300Vrms isolation voltage. Manufactured by Vishay Semiconductor Opto Division, this component is classified as obsolete. Due to its obsolete status, equivalent substitute parts from active manufacturers are necessary for new designs and ongoing production requirements. Substitute parts maintain the same package format (6-DIP), isolation voltage rating, and functional output configuration while offering active product status and improved availability.

Key Parameters

Parameter	IL203 Value
Manufacturer	Vishay Semiconductor Opto Division
Product Status	Obsolete
Number of Channels	1
Voltage - Isolation	5300Vrms
Current Transfer Ratio (Min)	225% @ 10mA
Current Transfer Ratio (Max)	450% @ 10mA
Output Type	Transistor with Base
Voltage - Output (Max)	70V
Voltage - Forward (Vf) (Typ)	1.2V
Current - DC Forward (If) (Max)	60 mA
Vce Saturation (Max)	400mV
Operating Temperature	-55°C ~ 100°C
Mounting Type	Through Hole
Package / Case	6-DIP (0.300", 7.62mm)
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts are grouped by current transfer ratio (CTR) performance bands, which is the primary electrical parameter determining functional equivalence. All substitute parts share the following mandatory compatibility criteria with IL203:

Single channel configuration
6-DIP through-hole package (0.300", 7.62mm)
Transistor output with base connection
70V maximum output voltage
60 mA maximum DC forward current
Operating temperature range -55°C ~ 100°C
ROHS3 compliance and MSL 1 rating

Substitutes are organized into four CTR performance groups:

Group 1 (40-80% CTR): CNY17-1, CNY17-1X, CNY17-2, CNY17-2X Group 2 (100% CTR): CNY17-3, CNY17-3X Group 3 (160-320% CTR): CNY17-4, CNY17-4-000E, CNY17-4X, CNY17-5 Group 4 (200-400% CTR): CNY17-5

The IL203 operates in the highest CTR band (225-450% @ 10mA). Direct electrical equivalents are CNY17-4X and CNY17-5, which provide matching or superior CTR performance within the same package and isolation voltage class.

Parameter Comparison

Parameter	IL203	CNY17-1X	CNY17-2X	CNY17-3X	CNY17-4X	CNY17-5
Manufacturer	Vishay	Isocom	Isocom	Isocom	Isocom	Isocom
Product Status	Obsolete	Active	Active	Active	Active	Active
Voltage - Isolation	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms
CTR Min @ 10mA	225%	40%	63%	100%	160%	200%
CTR Max @ 10mA	450%	80%	125%	200%	320%	400%
Output Type	Transistor with Base	Transistor with Base	Transistor with Base	Transistor with Base	Transistor with Base	Transistor
Voltage - Output (Max)	70V	70V	70V	70V	70V	70V
Current - Output / Channel	Not specified	50mA	50mA	50mA	50mA	50mA
Voltage - Forward (Vf) (Typ)	1.2V	1.2V	1.2V	1.2V	1.2V	1.2V
Current - DC Forward (If) (Max)	60 mA	60 mA	60 mA	60 mA	60 mA	60 mA
Vce Saturation (Max)	400mV	400mV	400mV	400mV	400mV	400mV
Operating Temperature	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C
Package / Case	6-DIP	6-DIP	6-DIP	6-DIP	6-DIP	6-DIP
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

CNY17-4X and CNY17-5 are the preferred substitutes for IL203 replacement. Both parts are manufactured by Isocom Components 2004 LTD with active product status, ensuring long-term availability and supply chain stability. CNY17-4X provides CTR performance (160-320% @ 10mA) within the operational range of IL203 and maintains identical isolation voltage (5300Vrms), forward voltage (1.2V), and saturation voltage (400mV) specifications. CNY17-5 offers superior CTR performance (200-400% @ 10mA) with the same electrical and mechanical compatibility.

Secondary Substitutes (Conditional Use):

CNY17-2X and CNY17-3X are suitable for applications where lower CTR performance is acceptable. CNY17-2X provides 63-125% CTR, while CNY17-3X provides 100-200% CTR. Both maintain 5300Vrms isolation voltage and identical package specifications. These parts are appropriate for designs where the IL203's high CTR (225-450%) is not a critical requirement.

Not Recommended:

CNY17-1 and CNY17-1X operate at 5000Vrms isolation voltage (300V lower than IL203) and provide only 40-80% CTR. These parts are suitable only for applications with reduced isolation voltage requirements.

All recommended substitutes carry ROHS3 compliance and MSL 1 rating, matching the regulatory and environmental specifications of the original IL203.

Frequently Asked Questions (FAQ)

Q: Can CNY17-4X directly replace IL203 in existing designs?

A: Yes. CNY17-4X maintains identical package format (6-DIP), isolation voltage (5300Vrms), output type (transistor with base), and critical electrical parameters (Vf, Vce saturation, operating temperature). The CTR performance range (160-320% @ 10mA) overlaps with IL203 (225-450% @ 10mA), making it suitable for direct substitution in most applications.

Q: What is the difference between CNY17-4X and CNY17-5?

A: Both parts are manufactured by Isocom and share identical package, isolation voltage, and output configuration. The primary difference is CTR performance: CNY17-4X provides 160-320% CTR while CNY17-5 provides 200-400% CTR. CNY17-5 offers higher current transfer ratio, making it more suitable for applications requiring maximum optical coupling efficiency.

Q: Why are CNY17-1 and CNY17-1X not recommended as direct substitutes?

A: CNY17-1 and CNY17-1X operate at 5000Vrms isolation voltage, which is 300V lower than IL203's 5300Vrms rating. Applications requiring the full 5300Vrms isolation specification cannot use these parts. Additionally, their CTR performance (40-80% @ 10mA) is significantly lower than IL203.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed (CNY17-1, CNY17-1X, CNY17-2, CNY17-2X, CNY17-3X, CNY17-4, CNY17-4-000E, CNY17-4X, and CNY17-5) are ROHS3 compliant with MSL 1 rating, matching the regulatory status of IL203.

Q: What is the significance of the "X" designation in part numbers like CNY17-4X?

A: The "X" designation indicates the manufacturer is Isocom Components 2004 LTD. Parts without the "X" suffix (CNY17-1, CNY17-2, CNY17-4) are manufactured by Lite-On Inc. Both manufacturers produce functionally equivalent parts within the same CTR performance bands.

Q: Can I use CNY17-3X as a substitute if my application has lower current requirements?

A: CNY17-3X is compatible with IL203 in terms of package, isolation voltage, and output configuration. However, its CTR performance (100-200% @ 10mA) is lower than IL203 (225-450% @ 10mA). Use CNY17-3X only if your circuit design does not depend on the higher CTR performance of IL203.

Q: What is the current output capability difference between IL203 and substitute parts?

A: IL203 does not specify maximum output current per channel. Substitute parts specify 50mA maximum output current per channel (CNY17-1X, CNY17-2X, CNY17-3X, CNY17-4X, CNY17-5) or 150mA (CNY17-1, CNY17-2, CNY17-4). Verify your application's output current requirements against the substitute part's rated capability.

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